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CN-121974579-A - Cement clinker prepared from carbide slag completely replacing limestone and preparation method thereof

CN121974579ACN 121974579 ACN121974579 ACN 121974579ACN-121974579-A

Abstract

The invention provides a method for preparing cement clinker by completely replacing limestone with carbide slag, which comprises the steps of respectively crushing the carbide slag of a calcareous material, the coal-fired slag of a siliceous material, the slag soil of an aluminum material and the sulfuric acid slag of an iron material, uniformly mixing the crushed carbide slag and the crushed coal-fired slag of the siliceous material according to a proportion to form a mixture, preheating the mixture at a certain temperature to eliminate moisture before calcining, calcining the mixture at 1300-1500 ℃ for a certain time to enable various components to undergo chemical reaction to generate main components C3S, C2S and the like of cement, rapidly cooling the main components to avoid the transformation of beta-C 2 S to gamma-C 2 S, and finally forming the cement clinker. The cement clinker prepared by the method can replace limestone by 100%, so that the exploitation of natural limestone resources is saved, and the emission of greenhouse gas CO 2 is reduced. The method consumes a large amount of solid wastes such as coal-fired slag, slag soil, sulfuric acid slag and the like in a certain sense. Meanwhile, the energy consumption in the cement clinker production process is saved, and the industrial production efficiency is improved.

Inventors

  • XU YANXIA
  • Zhao Zhangxiang
  • YANG XIAOBO
  • HAN QIMING
  • WANG GUANGLE
  • SUN ZE

Assignees

  • 华东理工大学
  • 青海民族大学
  • 青海省新型建材工贸有限责任公司

Dates

Publication Date
20260505
Application Date
20251231

Claims (10)

  1. 1. The cement clinker prepared by completely replacing limestone with carbide slag is characterized in that the raw material comprises 65-75% of calcium carbide slag, 2-5% of siliceous coal slag, 15-25% of aluminum slag and 1-5% of ferrous sulfate slag in percentage by mass.
  2. 2. The cement clinker prepared by completely replacing limestone with carbide slag according to claim 1, wherein the carbide slag contains 40-80% of CaO, 1-5% of SiO 2 , 1-5% of Al 2 O 3 , 0.1-5% of Fe 2 O 3 , the coal-fired slag contains 1-5% of CaO, 50-80% of SiO 2 , 1-10% of Al 2 O 3 , 1-5% of Fe 2 O 3 , the clinker contains 1-10% of CaO, 40-60% of SiO 2 , 5-20% of Al 2 O 3 , 1-15% of Fe 2 O 3 , and the sulfate slag contains 1-5% of CaO, 20-40% of SiO 2 , 1-10% of Al 2 O 3 and 30-60% of Fe 2 O 3 .
  3. 3. The method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 1, which is characterized by comprising the following steps: step 1, fully grinding carbide slag, coal-fired slag, muck and sulfate slag into powder to obtain raw materials; Step 2, drying the mixture at 80-120 ℃ for 20-30 hours; Step 3, adding water into the mixture, wherein the mass of the water is 3-12% of that of the raw material, uniformly stirring, pressing the mixture into blocks under a certain pressure, and drying the blocks at 80-120 ℃ for 8-16 hours; And 4, calcining the dried raw material block at 900-1000 ℃ and 1300-1500 ℃ in sequence, and rapidly cooling to 60-120 ℃ after calcining.
  4. 4. The method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein the grinding in step 1 is performed by a ball mill, and the cement clinker is screened by a 100-300 mesh screen after grinding.
  5. 5. The method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein in step 1, pre-drying is performed before grinding, the pre-drying temperature is 60-80 ℃, and the drying time is 6-12h.
  6. 6. A method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein in step 3, the mass of added water is 5-10% of the mass of raw material, and the pressure is 20-40MPa.
  7. 7. A method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein in step 3, the raw material block is dried at 90-110 ℃ for 9-14 hours.
  8. 8. A method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein in step 4, the calcination process is heating to 900-1000 ℃ at 8-12 ℃ per min, preserving heat for 20-40min, then heating to 1300-1500 ℃ at 4-10 ℃ per min, and preserving heat for 30-80min.
  9. 9. A method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein the step 4 is carried out by calcining in a muffle furnace.
  10. 10. The method for preparing cement clinker by completely replacing limestone with carbide slag according to claim 3, wherein in step 4, the rapid cooling means cooling to 60-120 ℃ within 2-5 min.

Description

Cement clinker prepared from carbide slag completely replacing limestone and preparation method thereof Technical Field The invention relates to the fields of cement material science and industrial solid waste utilization, in particular to a method for preparing cement clinker by completely replacing limestone with carbide slag. Background The carbide slag is used as a large amount of solid waste (the main component is Ca (OH) 2) produced in chlor-alkali industry, has strong alkalinity, is piled up in a large amount and seriously pollutes the environment, and needs to be recycled. Meanwhile, the cement industry is used as a main CO 2 emission source, faces severe carbon reduction pressure, and the process CO 2 emission caused by calcium carbonate decomposition can be remarkably reduced by using calcium carbide slag rich in calcium sources to replace limestone raw materials. However, the prior art for producing cement clinker by using carbide slag has the fundamental bottleneck that Ca (OH) 2 in the carbide slag is dehydrated and absorbs heat in advance in a preheating system, so that the heat consumption is greatly increased and a large amount of water vapor is generated, the co-pole with the impurities such as alkali, sulfur, chlorine and the like in the raw material easily causes serious skinning and blocking of the preheater system to threaten the operation stability, and on the other hand, the high water content, fine granularity, viscosity and impurity fluctuation of the carbide slag cause difficult raw material preparation and transportation, and clinker mineral composition (such as low C 3 S content and high f-CaO) and performance are difficult to stably control under high doping amount (generally lower than 40%). The existing novel dry kiln system and process are mainly designed aiming at limestone, are difficult to adapt to the unique physical and chemical characteristics of high-doping carbide slag raw materials, and restrict large-scale and high-added-value utilization of carbide slag and deep carbon reduction in cement production. Therefore, development of a carbide slag high-utilization-rate low-carbon cement clinker preparation method capable of breaking through the limit of doping amount, guaranteeing stable operation of a system and realizing high-quality clinker production is needed. Disclosure of Invention Therefore, aiming at the technical problems of high carbon emission of cement prepared from the traditional limestone, low utilization rate of cement prepared from the carbide slag and the like, the invention provides a method for preparing cement clinker by completely replacing limestone with the carbide slag. The cement clinker prepared by completely replacing limestone with carbide slag is prepared by the technical scheme of the invention, and raw materials comprise, by mass, 65-75% of calcium material carbide slag, 2-5% of siliceous material coal-fired slag, 15-25% of aluminum material muck and 1-5% of ferrous material sulfate slag. The carbide slag is mainly a solid byproduct of acetylene production by the hydrolysis of calcium carbide, the reaction activity is higher than that of limestone in the sintering process, the carbon dioxide release is less, the coal-fired slag is a mineral melting-cooling product obtained by burning a coal-fired power plant or an industrial boiler, siO 2-Al2O3 is taken as a framework, the slag is obtained by mixing tailings obtained by processing resources/dressing and washing and aluminum-containing waste residues obtained by weathering of an industrial storage yard with soil, and building demolishing regeneration fine powder, al 2O3+SiO2 is taken as a main material, certain clay minerals (kaolinite/illite and the like) are often brought, the particles are fine and strong in plasticity, the uniform ingredients are facilitated, and the sulfuric acid slag is roasting slag/cinder obtained by preparing sulfuric acid from pyrite. The invention can completely replace limestone by using carbide slag, and has the core that the effective CaO source provided by the carbide slag is more active, the decomposition path is better, and the carbide slag and solid wastes such as Si/Al/Fe are easier to cooperatively generate clinker mineral phases in the sintering process, so that the calcium supply of the carbide slag is realized on the premise that the batching modulus (KH/SM/IM) is satisfied. Lime stone for supplying calcium CaCO 3→CaO+CO2 ∈ (CO 2 is required to be decomposed and released, the decomposition temperature area is higher, and CO 2 diffusion can affect the reaction) Calcium supplied by carbide slag Ca (OH) 2 → CaO + H2 O ∈h (dehydration temperature is lower, generated CaO is finer and more active) The synergistic effect is that the silicate phase is promoted to be generated by the cooperation of the aluminum silicate slag and siliceous materials (2-5 percent of coal slag), the aluminum silicate slag is cooperated with aluminum materials (15-25 percent of sl